A 1-Tesla MRI system for dedicated brain imaging in the neonatal intensive care unit

Abstract

ObjectiveTo assess the feasibility of a point-of-care 1-Tesla MRI for identification of intracranial pathologies within neonatal intensive care units (NICUs).MethodsClinical findings and point-of-care 1-Tesla MRI imaging findings of NICU patients (1/2021 to 6/2022) were evaluated and compared with other imaging modalities when available.ResultsA total of 60 infants had point-of-care 1-Tesla MRI; one scan was incompletely terminated due to motion. The average gestational age at scan time was 38.5 ± 2.3 weeks. Transcranial ultrasound (n = 46), 3-Tesla MRI (n = 3), or both (n = 4) were available for comparison in 53 (88%) infants. The most common indications for point-of-care 1-Tesla MRI were term corrected age scan for extremely preterm neonates (born at greater than 28 weeks gestation age, 42%), intraventricular hemorrhage (IVH) follow-up (33%), and suspected hypoxic injury (18%). The point-of-care 1-Tesla scan could identify ischemic lesions in two infants with suspected hypoxic injury, confirmed by follow-up 3-Tesla MRI. Using 3-Tesla MRI, two lesions were identified that were not visualized on point-of-care 1-Tesla scan: (1) punctate parenchymal injury versus microhemorrhage; and (2) small layering IVH in an incomplete point-of-care 1-Tesla MRI with only DWI/ADC series, but detectable on the follow-up 3-Tesla ADC series. However, point-of-care 1-Tesla MRI could identify parenchymal microhemorrhages, which were not visualized on ultrasound.ConclusionAlthough limited by field strength, pulse sequences, and patient weight (4.5 kg)/head circumference (38 cm) restrictions, the Embrace® point-of-care 1-Tesla MRI can identify clinically relevant intracranial pathologies in infants within a NICU setting.

Managing Patients With Unlabeled Passive Implants on MR Systems Operating Below 1.5 T

“…8,[12][13][14][15][16][17][18] Substantial improvements in hardware and software have resulted in a resurgence in MR systems operating below 1.5 T. An array of different scanner geometries, field strengths, and different use-cases are found in this realm including an open-architecture, vertical (transverse) field 1.2 T scanner and the lower field strength (generally defined as MR systems operating in the range of 0.25 to 1.0 T) MR systems that have horizontal (longitudinal) or vertical (transverse) field magnets. 10,11,[19][20][21][22] Also operating below 1.5 T are scanners with unique features or designed for specialized applications such as a very-low-field (0.064 T), point-of-care MR system, 23,24 dedicated extremity scanners, 25,26 an upright MR system, 27 a neonatal scanner, 28 an MRI-guided, radiotherapy system, 29 and a single-sided, interventional MR scanner. 30,31 The growing worldwide utilization of these MR systems combined with the increasing incidence of patients with metallic implants that need MRI creates undesirable circumstances that include patients potentially being subjected to unsafe imaging conditions or being denied access to MRI because physicians often lack the knowledge to conduct a proper assessment of risk vs. benefit.…”

“…Substantial improvements in hardware and software have resulted in a resurgence in MR systems operating below 1.5 T. An array of different scanner geometries, field strengths, and different use‐cases are found in this realm including an open‐architecture, vertical (transverse) field 1.2 T scanner and the lower field strength (generally defined as MR systems operating in the range of 0.25 to 1.0 T) MR systems that have horizontal (longitudinal) or vertical (transverse) field magnets 10,11,19–22 . Also operating below 1.5 T are scanners with unique features or designed for specialized applications such as a very‐low‐field (0.064 T), point‐of‐care MR system, 23,24 dedicated extremity scanners, 25,26 an upright MR system, 27 a neonatal scanner, 28 an MRI‐guided, radiotherapy system, 29 and a single‐sided, interventional MR scanner 30,31 …”